1. Field of the Invention
This invention relates generally to communications networks. More particularly, it relates to telecommunications networks including Voice Over Internet Protocol (VoIP) network communications, and most particularly to SIP (Session Initiation Protocol) emergency service messaging via IP telecommunications for voice, video, and text.
2. Background of the Related Art
Session Initiation Protocol (SIP) is a basic protocol for initiating interactive communication sessions (e.g., voice, video, chat, interactive games, virtual reality, etc.) between users. In given SIP-based applications, location of a particular wireless device is desired or required.
Currently, location and other caller-related data for the majority of calls (VoIP, cellular, or landline) is delivered or determined through multiple mechanisms. For instance, location and other data for the majority of calls is determined via the use of a unique query key (such as the telephone number or uniform resource identifier (URI)) to perform a database lookup. In these architectures, the unique query key (e.g., telephone number or URI) is used as a lookup element to query provisioned, staged or static information (e.g., from a suitable database) outside of the actual call signaling for location information. An exemplary technique and apparatus to inject a location object into a routing SIP message is disclosed in co-owned U.S. patent application Ser. No. 11/902,845, filed Sep. 26, 2007, the entirety of which is expressly incorporated herein by reference.
FIG. 3 shows a conventional exemplary Voice over Internet Protocol (VoIP) based routing architecture for a given Session Initiation Protocol (SIP) message.
In particular, as shown in FIG. 3, a Session Internet Protocol (SIP) message includes a unique query key, or location key (e.g., telephone number or URI) to be used to determine an action based on the initiator's location (i.e., position). As shown in FIG. 3, the SIP message including the unique query (e.g., location) key is passed to a positioning center 502.
Using the received location key, the positioning center 502 passes a query to an appropriate database 504, e.g., a database associating static location with various location key information. The static location database 504 determines the desired location information relating to the input location key, and returns the static location to the requesting positioning center 502.
Then, having obtained appropriate location information, the positioning center 502 passes a request to another database, e.g., a routing database 506, to obtain routing information associated with the received location information. The routing database 506 outputs appropriate routing information to the requesting positioning center 502. At that point, the positioning center 502 passes on the SIP message together with new routing information obtained from the routing database 506.
Standards development groups have created a mechanism for providing location associated to an endpoint or anchor point within a SIP session (“call”). Moreover, discussions have taken place promoting the idea of providing a limited set of URIs (Uniform Resource Identifiers) with the SIP messaging.
But a mechanism has not been heretofore provided to provide associated “ancillary” data with the call. The present inventors realize that such a mechanism is desired to support emergency calling as a primary application, and could be extended into commercial uses.
Disadvantages of the prior technology includes, e.g., providing a limited set of URIs, is not sufficient to cover all known or eventual types of data that are or will be required. Moreover, by providing URIs only, there is no provision for including (embedding) ancillary data within the SIP body part. Furthermore, body part(s) as a separate package can be easily encrypted while the headers remain in plain text. (Providing one or more URIs as the only option cannot ensure that the data associated with it will be delivered in an encrypted or digitally signed manner, whereas a mechanism for embedding the data within the SIP message itself allows for its encryption and/or digital signature as required.)